Portland cement has been used in concrete for nearly two centuries. But, Portland cement generally requires energy-intensive production facilities sufficient to process limestone at 2,000° F. in mammoth kilns. About one pound of carbon dioxide is released to the atmosphere for every pound of Portland cement produced. While Portland cement is used in many concrete structures, Portland cement also contributes significantly to decay of installed infrastructure as Portland cement deteriorates, especially due to attack from chloride ions.
Magnesium cement is suitable as a substitute for Portland cement. At present, magnesium cements are derived from magnesium oxide and are therefore relatively costly and relatively complicated products. Marketed products involving magnesium cement are primarily limited to the interior wall applications, such as magnesium oxychloride cement boards. Magnesium oxychloride cement experiences a strength loss when wet as a result of leaching of magnesium chloride and other chloride components. Another magnesium cement, magnesium oxysulfate cement, also loses strength when wet because it still has a relatively significant magnesium chloride component. Such strength reduction is a major obstacle to other structural uses of magnesium cement. Other magnesium cements provide high performance, but have limited raw material supplies, cannot be wet-cured, and are otherwise ten-fold more expensive than Portland cement.
A more sustainable material is needed to replace Portland cement, especially a material has superior mechanical properties and duty life, especially in wet duty service, while being reasonably priced.